将Listbox绑定到ObservableCollection <T> 不工作的WPF

Question

I have a JobItem object, and inside it, I have:

public ObservableCollection<string> BusinessUnit
    {
        get 
        { 
            return businessUnit; 
        }
        set { businessUnit = value; } 

    }

Now the user needs to fill in a form and add in multiple Business Units. I have created a listbox that has add and delete buttons beside it. The add button opens a dialog that prompts the user to add the name of the business unit, then adds it to the list box. This is the code I have for this:

<my:ValidatingListBox Grid.Column="1" Grid.ColumnSpan="1" Grid.Row="5" Grid.RowSpan="1" x:Name="businessUnitBox" SelectionMode="Multiple" SelectionChanged="ValidatingListBox_SelectionChanged" IsSynchronizedWithCurrentItem="True">
            <my:ValidatingListBox.ItemsSource>
                <Binding Source="{StaticResource jobItemDataSource}" Path="BusinessUnit" Mode="TwoWay"/>
            </my:ValidatingListBox.ItemsSource>
            </my:ValidatingListBox>

    <Button Style="{StaticResource addBtnStyle}" Grid.Column="2" Grid.Row="5" Name="addBusinessUnitBtn" Click="addBusinessUnitBtn_Click" />
    <Button Style="{StaticResource removeBtnStyle}" Grid.Column="2" Grid.Row="5" Name="delBusinessUnitBtn" Click="delBusinessUnitBtn_Click" />

In the code behind, I'm binding the JobItem to the form because I have other textboxes that are bound to other JobItems (the binding works for this).

public NewJobDialog(int workOrderCounter)
    {
        InitializeComponent();
        item = new JobItem();
        base.DataContext = item();
        businessUnitBox.DataContext = item.BusinessUnit;
     }

Then when I click on the add button to add a business unit, I have this code:

private void addBusinessUnitBtn_Click(object sender, RoutedEventArgs e)
    {
        AddBusinessUnitDialog addBusinessUnit = new AddBusinessUnitDialog();
        addBusinessUnit.ShowDialog();

        if (addBusinessUnit.DialogResult == true)
        {
            item.BusinessUnit.Add(addBusinessUnit.BusinessUnit());
        }

    }

    private void delBusinessUnitBtn_Click(object sender, RoutedEventArgs e)
    {
        if (businessUnitBox.Items.Count > 0)
        {
            item.BusinessUnit.Remove((string)businessUnitBox.SelectedItem);
        }

    }

Now when I run the program, every time I add a business unit, it does not show up in the listbox. Please give me some type of sample code as to how I would be able to get this to work. Thanks.

Answer 1

I believe it is because you need to set the DataContext to the parent class.

businessUnitBox.DataContext = item;

This is because you have the following binding

<Binding Source="{StaticResource jobItemDataSource}" Path="BusinessUnit" Mode="TwoWay"/>

Additionally you can simplify the binding by having..

<my:ValidatingListBox ItemsSource="{Binding BusinessUnit}" ... />

EDIT:

If you really want

businessUnitBox.DataContext = item.BusinessUnit;

Then your binding needs to be

<my:ValidatingListBox ItemsSource="{Binding Path=." ... />